Space heater



March 2, 1965 w. B. K|RGAN 3,171,399

SPACE HEATER Filed Augll, 1961 4 Sheets-Sheet 1 INVENTOR.

Y WALTER B. KIRGAN ATTORNEYS W. B. KIRGAN SPACE HEATER March 2, 1965 4 Sheets-Sheet .2

Filed Aug. 11 1961 IN V EN TOR.

WALTER B. KIRGAN i ATTORNEYS w. a M M J 2 FIG-2 March 2, 1965 w. s. KIRGAN 3,171,399

SPACE HEATER Filed Aug. 11, 1961 4=Sheets-Sheet 3 FIG-4 HI wil lm 88 5'4 92 I FIG-5 I I07 IN V EN TOR.

WALTER B. KIRGAN ATTORNEYS l u .l.' I

March 2, 1965 w. B. KIRGAN 3,171,399

SPACE HEATEB Filed Aug. 11, 1961 4 Sheets-Sheet 4 76 79 FIG 8 1 M 88 FIG -10 83 I33 82! 75 f la 74 I40 '5 I46 55 I4! ISI I; 3 I36 3a 5 I25 I25 Ii ll )2! I2 2 INVEN TOR.

WALTER B. KIRGAN Y.

ATTORNEYS 3,171,399 i atented Mar. 2, 1965 3,1715% SPAQE HEATER Walter B. Kirgan, Fort Recovery, Ohio, assignor to Qualified Range Company, Inez, Fort Recovery, Ohio, a corporation of @hio Filed Aug. 11, 1961, Ser. No. 131,712 6 Claims. ((11. 126110) This invention pertains to wood burning space heaters and more particularly to such a heater providing radiant and forced air heating. This application is a continuation-in-part of the copending application of Kirgan, Ser. No. 42,833, filed July 14, 1960, now abandoned.

This invention provides an efficient wood burning space heater which is arranged to recapture much of the heat of the flue gases so that such gases are discharged with a substantial portion of their heat energy removed. At the same time, the heater provides direct radiant heat from the front and sides of the fire box. The heater includes a blower system which draws in room air across the top of the fire box and removes the heat at an area of high concentration. The air thus heated is further circulated downwardly at the back of the heater in a direction generally counter to the path of the flow of the flue gases, and is discharged by a blower system adjacent the floor level. The heater in one embodiment also includes an air cooled fire box wherein draft air is circulated around the back, sides and front of the fire box, including provision for forced draft and cooling.

It is therefore an object of this invention to provide a wood burning space heater as outline above having combined radiant and forced air heating.

A further object of this invention is to provide a wood burning space heater as outlined above characterized by versatility and adaptability to a wide variety of heating and installation requirements.

Another object of this invention is to provide a wood burning space heater as outlined above character'med by efficiency in the utilization of the heat energy from the burning wood and arranged to provide room heat in regions where it is needed.

A still further object of this invention is the provision of a space heater as outlined above including an air cooled fire box which is protected against burn-out by the circulation of draft air and which may include provision for forced draft.

Other objects and advantages of the invention will be apparent from the following description, the accompanying drawings and the appended claims.

In the drawings FIG. 1 is a front view of a Wood burning space heater according to this invention with a portion of the front wall partially broken away to expose the arrangement of internal components;

FIG. 2 is a vertical section through the heater taken generally along the line 2-2 of FIG. 1;

FIG. 3 is a transverse section through the heater with the fire brick and grates removed, but showing a corner portion of the fire brick, and taken generally along the line 3-3 of FIG. 2;

FIG. 4 is another vertical section through the heater taken generally along the line 4-4 of H6. 1;

FIG. 5 is a partial section through the fire box showing the arrangement of the fire brick on one side thereof taken generally along the line 55 of FIG. 4;

FIG. 6 is an elevational view of the fire brick arrange ment of FIG. 5;

FIG. 7 is a fragmentary detail of the air louvers in the air discharge opening;

FIG. 8 is a transverse section through a modified form of the heater similar to FIG. 3, above;

FIG. 9 is a fragmentary vertical section through the modified form of the heater corresponding to the righthand portion of FIG. 1;

FIG. 10 is a fragmentary section through the back of the heater taken generally along the line 10-10 of FIG. 8 showing the adjustable natural draft opening;

FIG. 11 is a further vertical section through the back of the heater taken generally along the line 11-11 of PEG. 8 showing the arrangement of the adjustable forced draft; and

FIG. 12 is a further enlarged section taken generally along the line 1 212 of FIG. 8 through the front grate supporting frame showing the draft openings formed therein.

Referring to the drawings, which illustrate preferred embodiments of the invention, a wood burning space heater is illustrated generally at 10 in FIG. 1 as having a sheet metal outside cabinet supported on legs 11. The front wall 12 of the heater 161 includes an entrance or loading door 14 opening to the interior of the fire box for supplying wood to the heater. An ash pan door 15 opens into the fire box below the grates and has a sliding draft plate 16. The fire box 29 of the heater 10 consists of the front wall 12, an inner back wall 21, side walls 22 and 23 forming the sides of the heater, a top enclosing plate 2 2- and a bottom plate 25 forming the bottom of the heater.

Means for supporting an ash pan and grate in the fire box 29 and for defining flue passages at the sides of the grates includes a generally U-shaped metal frame 28 having turned side flanges 29 welded to the front and back walls 21 and 12 of the fire box 20. The frame 28 includes a transverse bottom or base portion 30 extending substantially across the width of the fire box spaced from the bottom plate 25 and connecting with spaced apart upstanding side portions 31 and 32 spaced from the side walls 22 and 23 respectively. The base portion 30 extends between and its welded to the front and back walls 12 and 21 of the fire box. A grate supporting platform or shelf 35 is circumferentially secured, as by welding, to the inside surface of the side portions 31 and 32 of the frame 28 and to the inside surfaces of the front and back walls 12 and 21 for supporting a grate assembly.

The grate assembly consists of a cast iron frame 36 and rotatable shaker grate portions 37 and 38 supported therein. Fire bricks 4d are supported in upstanding relation on the grate frame 36 and are held in position at the lower end thereof by a circumferentially raised lip 41 formed in the frame 36. The fire bricks adjacent the front and back walls of the fire box are received against inclined sheet metal back-up plates 43 and 44.

The fire bricks 41) at the sides, in this embodiment, are supported directly against the vertical inside surfaces of the side portions 31 and 32 of the frame 28 which therefore provides back-up plate protection and support for such side bricks. A removable ash pan 48 is supported on the upper surface of the bottom portion 30, and is held in position by a track formed with a pair of spaced apart angles 49.

The side portions 31 and 32 of the frame together with the side walls 22 and 23 of the heater provide passageways 51 and 52 between the grates and the side walls extending from the space above the fire brick and opening at a region below the ash pan 43 for the flow of hot flue gases downwardly adjacent the sides of the heater. The bottom portion 30 of the frame 28 and the bottom enclosing plate 25 of the fire box form a flue gas collection chamber 54 for receiving hot flue gases from the passageways 51 and 52.

The side walls 22 and 23 of the heater extend rearwardly beyond the inner back wall 21 to an outer back plate 55 Verflue pipe opening at its bottom into the collection chamber 54 through the bottom opening 58 in the plate 21. The pipe 60 opens at its top into an externally mounted check draft box 61-;for discharge of flue gases into a chimney 62. l

An opening 63 is formed in the back wall 21 to provide a direct draft to the chimney 62 when a fire is first built.

A damper plate. 65 is pivotally movableby an external handle 66 between a starting position which closes the pipe 60 and provides for direct escapeof'flue gases, anda normal position covering'the opening 63 and providing for flue gas fiow only through the pipe-69. In the normal position the hue gases are caused to flow downwardly through the side passageways 51 and 52 adjacent the sides of the heater for collection in the chamber 54 adjacent the bottom plate 25 then upwardly through the pipe 60 into the chimney 62. 'The heater front wall 12, side Walls 22 and 23 and a portion of the back plate 55 will primarily radiate heat into the room.

Means for removing heat from the top, back and bottom'of the fire box includes a forced air system having an air inlet 70 extending across the top plate 24 of the fire box. The inlet 70 is defined by a cap or'cover 71 which is opened at the front and forms an inlet passageway 72 extending from the front to the back of the heater.

The vertical spacers 56 and 57 together with the wall 21 and plate 55 also form vertical heated air passageways 74 and 75 adjacent each side of the flue pipe 6% and the back wall 21 of the fire box. The passageways 74 and 75' are opened at their upper ends into the .inlet passageway72 to receive heated air from the heater top. A blower unit 76 consisting of a motor 77 and a pair of blowers 78 and removal of one or more or" the individual fire bricks 40 at,

the side of the fire box. These bricks are shown in FIG. 6 as includinga pair of upstanding support bricks and 101, which are notched at 102 to receive the ends of an intermediate brick 193. The adjoining corners of the bricks 1th) and ltll may be mitered at 104 to assist in retaining the bricks in place. A removable center brick 195 rests on the top of the intermediate brick 103, and

a pair of smaller bricks107 and 108 are positioned beneath the'intermediate brick 104 to rest on the grate frame 36. The support bricks 100 and 101 and the removable 'center brick 1&5 are formed with an overhanging ledge 109 for engagement with the upper edge of the frame 28.

7 One or both of the adjacent side portions 31 and 32 of the frame 28 may be formed. withrectangular cut-out openings 11%, as shown in FIG. 4,'which are positioned generally adjacent to, and are somewhatsmaller than the removable bricks 105. One or both of the bricks may V the particular installation may dictate.

79 includes inlet tubes 82 and 83 which are connected respectively to the passageways 74 and 75 to draw heated air therefrom. A, bathe plate 84 provides heat protection for the motor 77, and a further baffle plate 85 protectsa motor control switch 86.

A hot air discharge conduit in the form of a pan or compartment 88 isformedat the bottom of the fire box and has as its upper wall, thebottom plate 25. The compartment 88 is extended rearwardly of the fire box for connection with the blowers 78 and 79 and is' opened at ht across the front of the heater 10 for the discharge of heated air at floor level. A-plurality' of louvers'91 may be pivotally mounted at the outlet 90, as showngin FIG. .7, for the direction of the heated air as desired. Also,'a pair of side vents 92 formed of L-shaped stock may be pivotally mounted to swing inwardly by a handle 93, to direct heated air out at the stove sides as wellv as at the front. 1

It is therefore seen that the air circulating system draws in room air across the top of the fire box for heating by the top plate 24 at the region of normally greatest heat concentration. Such heated air is then drawn along the back surface of the fire box through the passageways 74 and 75 adjacent each side of the flue pipe 61 for ultimate discharge through the compartment 88 at the bottom of the fire box into t-he'room at floor level. This direction of a air flow is generally opposite to that of the heat flowwith the coolest air being applied at the regions of greatest heat concentration. a a Q The invention further provides-an arrangemenbwhereby the heater may be modified for the purpose of adaptation to a chimney which may have an otherwise inadequatedraft or for more efficient performance with a low burning fire. This is accomplished by shortening the path through which thefiue gases are caused to travel, by the l There may be circumstances where his. desired to shorten further the downward path of thefiue gases, such as where 'a low burning fire is usually maintained, or

where it isdesired to remove heat directly from the coals and embers of a wood fire which has essentially burned itself down to the point where the greatest concentration of heat is located-relatively deep within the grates. The stove may thus include a further opening formed in one or both of the side portions 31 and 32 adjacent the brick 107'. The bricks 107 may be removed to expose the opening 115 thereby further shortening the path of the flue. gases, as necessary or desired. a

A modified form of the invention is shown in FIGS. 8-l2 wherein like reference numerals are employed to designate like parts. This embodiment provides means forming an air passageway which completely surrounds a the brick of the fire box. This air passageway forms the sides and the front" of the firebox provides for long life of'the fire brick and especially of the'fire brick back-up or retaining plates, and prevents the burning-through of such plates. r I

As described above in connection with the embodiment of FIGS. I -7, the. fire brick'back-up plates 4'3and 44 are inclined with their bottoms set inwardly in respect to 7 their brick-retaining tops 45 and 46 and provide an inof the heater.

. side portions '32 and '31. One of the plates is shown in FIG. 9, andconsists of an inclined support means for the fire brick at the side instead of placing the brick directly against the inside surface of the side portions 31 and 32 of the frame 28. Therefore, an annular space which is generally triangularin section is formed about the 'fire box defined bythe back-up plates '43, 44 and 120,

121 and the fire brick is supported thereon. In the'operation of the heater, air is caused to circulate within the space 125 around the fire box to prevent the v burn-through of the back-up plates for the fire brick.

This circulation preferably forms the draft to the fire'.

. Therefore, .the invention includes'means connecting the space 125 to the space immediately below' the fire box in order that the fire therein may draw air for combustion therethrough. Such means includes openings 127 formed in the inwardly turned bottom leg 128 of the front backup plate 44 which communicate with a plurality of transverse openings 129 formed throughthemost forward edge of the annular grate support 35. The cast iron grate frame 36 is preferably provided with a fore-shortened front supporting ledge 130 so that it does not interfere with the air flow from the space 125 into the region immediately below the fire box and the grates.

The back flue compartment of this embodiment is modified to provide separate conduits for the vertical air passageways 74 and 75 and the flue pipe 60 thus providing a space between the passageway 74 and the flue 60 on one side and between the passageway 75 and the flue on the other side. These spaces are utilized to provide controllable damper means connecting the annular space 125 to the outside air to provide for draft air for the fire within the fire box. When the air circulating feature of this embodiment is employed, it is preferable to close the sliding draft plate 16 on the front of the heater. Alternately, this draft plate may be omitted in this embodiment.

Natural draft means on the back wall 21 communicating with the passageway 125 includes a slide plate 131 which is arranged for limited vertical movement on the outside surface of the back wall within a pair of guides 133. The plate 131 may include a handle 135 for convenience in adjusting. The slide plate 131 is movable selectively to uncover a draft aperture 136 formed within the plate 55 to regulate the amount of air admitted into the fire box by means of the circulation through the passageway 125 around the back surface of the fire bricks.

Forced draft means may be conveniently provided, if desired, by connecting the passageway 125 to the outlet of the blower unit 76. This may be conveniently done by a tube 140 which opens into the compartment 88 and which extends upwardly and inwardly and terminates at the back wall 21 between the flue pipe 60 and the vertical passageway 75. The tube 140 operates to supply air for combustion from the compartment 88 into the passageway 125 surrounding the fire brick through an aperture 141 formed within the back wall 21. A slide 145 is positioned on the back wall and moves within guides 146 for selectively opening and closing the aperture 141 to control the amount of air supplied by the blower unit 76 for combustion within the fire box, The slide may be conveniently operated by a handle 150. By this arrangement, additional air for combustion may be supplied during the initial starting of the fire, and this is helpful particularly when burning hard woods or where the wood is damp. Subsequent to starting, it is anticipated that the slide 145 will be operated to close off the forced draft and combustion air may then be supplied and circulated around the entire circumference of the fire box within the passageway 125 through the draft opening 136.

It is therefore seen that this invention provides a wood burning space heater which is arranged to utilize to a considerable extent the heat energy of the wood and which provides both radiant and direct room heating. In one embodiment, the fire brick and sheet metal backup plates are protected from burn-out by circulating the draft air within a compartment formed by the back-up plates and the front side and back walls of the fire box.

While the forms of apparatus herein described constitute preferred embodiments of the invention, it is to be understood that the invention is not limited to these precise forms of apparatus, and that changes may be made therein without departing from the scope of the invention which is defined in the appended claims.

What is claimed is:

1. A wood burning space heater comprising a fire box having a front wall forming the front of the heater for direct radiation therefrom, a back wall, side walls forming the sides of the heater for direct spatial radiation, a top and a bottom, a grate in said fire box for supporting wood to be burned, an ash pan compartment beneath said grate in said fire box, means defining passageways between said grate and said side walls extending from above said grate and opening below said ash pan compartment for the flow of hot flue gases downwardly adjacent the sides of said heater, means adjacent the bottom of said heater defining a flue gas collection chamber for receiving hot flue gases from said passageways, means on said back defining a fiue pipe opening at the bottom into said chamber and arranged to conduct said flue gases upwardly adjacent said back wall for discharge into a chimney, a forced air system for removing heat from said top, back wall and bottom of said fire box for conduction therefrom including a cap secured to said fire box top and defining with said top an air inlet passageway opening at the front of Said heater and extending across said top, a pair of heated air passageway conduits positioned on either side of said flue pipe with one side thereof including said back wall and opening into said inlet passageway, blower means mounted on said heater and having an inlet arranged to withdraw heated air from said passageway conduits, and means including said fire box bottom defining a hot air discharge conduit extending across said heater at said bottom connected to receive heated air from said blower adjacent said flue gas collection chamber for the removal of heat from said bottom and the discharge of heated air at floor level.

2. A wood burning space heater comprising a fire box having a front wall forming the front of the heater, :1 back wall, side walls forming the sides of the heater, a top and a bottom, a grate in said fire box for supporting wood to be burned, a frame extending between said front and back walls and with said side walls defining passageways extending from above said grates and opening below said grate and defining with said bottom a flue gas chamber for the flow of hot flue gases downwardly adjacent the sides of said heater into said chamber, a flue pipe opened at the bottom into said chamber and arranged to conduct flue gases upwardly adjacent said back for discharge into a chimney, a forced air system for removing heat from said top, back wall and bottom of said fire box including means defining an air inlet passageway extending across said top, heated air passageways positioned adjacent said back wall for the removal of heat therefrom and being opened at the top into said inlet passageway, blower means mounted on said heater and having an inlet arranged to withdraw heated air from said heated air passageways, a hot air discharge conduit extending across said fire box bottom connected to receive heated air from said blower and having a discharge opening at floor level for the discharge of heated air, fire brick arranged in surrounding relation to said grate, means in said fire box defining an enclosed annular air space surrounding said brick, means connecting said space for the supply of draft air to said grates, and means connecting said blower to said space for the supply of a forced air draft.

3. A space heater, comprising a fire box having a front wall forming the front of the heater, a back wall, side walls forming the sides of the heater, a top and a bottom, a generally Ushaped unitary frame received in said fire box extending from said front wall to said back wall, said frame having a pair of upwardly turned side portions connected by a transverse base, said side portions being spaced from said side walls of said fire box forming generally vertically extending flue gas passages With said side walls opening into a fiue gas collection chamber defined by said base and said fire box bottom, grate supporting platform means on said frame in spaced relation to said base, a wood burning grate received on said frame, a flue pipe opening at the bottom into said chamber and extending upwardly adjacent said back wall for conducting flue gases upwardly from said chamber for discharge into a chimney, a forced air system for removing heat from said top, back wall and bottom of said fire box for conduction therefrom including an inlet conduit enclosing said fire box top and having means defining an air inlet passageway opening at the front of said heater for removing heat from said top, a pair of heated air passageway conduits positioned on said back wall on either side of said flue pipe and opening into said inlet conduit for removing heat from said back wall, blower means mounted on said heater and connected to withdraw heated air from said passageway conduits,

and means including said fire box bottom defining a hot air discharge conduit extending acrosssaid heater at said bottom connected to receive heated air from said blower adjacent said flue gas collection chamber for the removal of heat from said bottom and the discharge of heated air at floor level. V

4. The'heater of claim 3 further having a plurality of fire brick, circumferential support means supporting said fire brick adjacent said grate in surrounding relation thereto and defining with said front and back walls and with said upwardly turned side portions an annular air space in surrounding relation to said fire brick, and means venting said space into the interior of said heater for convection flow therethrough for cooling said fire brick.

V 5. The heater of claim 3 further including a plurality of fire brick, means positioning said brick about said grate in surrounding relation thereto, means in at least one of said upwardly turned side portions defining an openin'gadjacent 8 said opening to a fire in said grate for shortening the length of travel of said flue gases from said grate to said flue gas collection chamber permittingta lower burning fire.

I 6. The space heater of claim 1 wherein said heated air passageway conduits are; positioned in'contiguous relation on each side of said flue pipe with'each side wall of said fiuepipe. forming a common divider with a corresponding conduit for the transferof heat from said-flue pipe through said walls into. said conduits;

References Cited; in the; file of this patent.

UNlTED STATES PATENTS 914,923 v Cahoone Mar. 9 1,691,208 Pedersen ca Nov. 13, 1928 2,146,122 r Lee Feb. 7,1939 2,356,705 Si e'gler et al Aug. 22, 1944 2 ,545,680 Wyatt Mar. 20, 1951 2,569,781" Schrank ----e,-- OCt. 2-, 1951 2,380,717 Tilmann Apr. 7, 1959- FOREIGN PATENTS 541,722 Germany Jan. 15,1932 

1. A WOOD BURNING SPACE HEATER COMPRISING A FIRE BOX HAVING A FRONT WALL FORMING THE FRONT OF THE HEATER FOR DIRECT RADIATION THEREFROM, A BACK WALL, SIDE WALL FORMING THE SIDES OF THE HEATER FOR DIRECT SPATIAL RADIATION, A TOP AND A BOTTOM, A GRATE IN SAID FIRE BOX FOR SUPPORTING WOOD TO BE BURNED, AN ASH PAN COMPARTMENT BENEATHS SAID GRATE IN SAID FIRE BOX, MEANS DEFINING PASSAGEWAYS BETWEEN SAID GRATE AND SAID SIDE WALLS EXTENDING FROM ABOVE SAID GRATE AND OPENING BELOW SAID ASH PAN COMPARTMENT FOR THE FLOW OF HOT FLUE GASES DOWNWARDLY ADJACENT THE SIDES OF SAID HEATER, MEANS ADJACENT THE BOTTOM OF SAID HEATER DEFINING A FLUE GAS COLLECTION CHAMBER FOR RECEIVING HOT FLUE GASES FROM SAID PASSAGEWAYS, MEANS ON SAID BACK DEFINING A FLUE PIPE OPENING AT THE BOTTOM INTO SAID CHAMBER AND ARRANGED TO CONDUCT SAID FLUE GASES UPWARDLY ADJACENT SAID BACK WALL FOR DISCHARGE INTO A CHIMNEY, A FORCED AIR SYSTEM FOR REMOVING HEAT FROM SAID TOP, BACK WALL AND BOTTOM OF SAID FIRE BOX FOR CONDUCTION THEREFROM INCLUDING 